I was out yesterday, and between rain on Sunday and the humidity the trees I was sitting under were dripping on me like it was pouring rain. It was warm, but once my pants got soaked it didn't feel so warm. I bailed at around 8:30. My pack is still damp.
We had to help my FIL built a shed yesterday and it completely wrecked my back and knees, so this heat wave won't bother me much as I'm out of the running anyway.